今日更新:Composites Part A: Applied Science and Manufacturing 1 篇,Composites Part B: Engineering 2 篇,Composites Science and Technology 1 篇
High toughness, flexible and thermally conductive fluorine rubber composite films reinforced by hexagonal boron nitride flakes for thermal management
Jing Chen, Yibing Lin, Wanbiao Hu, Yuanlie Yu
doi:10.1016/j.compositesa.2024.108466
热管理用六方氮化硼片增强的高韧性、柔性和导热氟橡胶复合薄膜
The rapid advancement of electronic information technology has generated a substantial demand for polymer-based thermal management materials. In order to address the challenges of heat dissipation and avoid signal interference, it is essential to develop polymer-based thermal management materials with both high thermal conductivity and low dielectric properties. Herein, hexagonal boron nitride flakes (h-BNFs) with a high aspect ratio and some hydroxyl groups were prepared using the high pressure homogenization technique. Subsequently, h-BNF/fluorine rubber (h-BNF/FKM) composite films were fabricated through a simple and scalable blade coating method. During the blade coating process, most of the h-BNFs can align with their (002) crystal planes paralleling to the horizontal direction. In addition, the rest of the h-BNFs will randomly distribute and overlap with each other, combining with the horizontally aligned h-BNFs to form a distinctive three-dimensional packing network. This unique network structure enables the h-BNF/FKM composite films to have thermal conductivities of up to 0.44 W/(m·K). Moreover, the introduction of h-BNFs can effectively reduce the dielectric constants and dielectric losses of FKM films. More importantly, the h-BNF/FKM composite films also exhibit outstanding mechanical toughness, excellent flexibility, good adhesion and improved flame-retardancy, providing promising applications in the electronic device thermal management.
电子信息技术的快速发展对聚合物基热管理材料产生了巨大的需求。为了解决散热和避免信号干扰的挑战,必须开发具有高导热性和低介电性能的聚合物基热管理材料。本文采用高压均质技术制备了具有高长径比和羟基的六方氮化硼薄片(h-BNFs)。随后,通过简单、可扩展的叶片涂覆方法制备h-BNF/氟橡胶(h-BNF/FKM)复合薄膜。在叶片涂覆过程中,大多数h- bnf能与平行于水平方向的(002)晶面对齐。此外,其余的h- bnf将随机分布并相互重叠,与水平排列的h- bnf结合,形成独特的三维填充网络。这种独特的网络结构使h-BNF/FKM复合膜的导热系数高达0.44 W/(m·K)。此外,h- bnf的引入可以有效降低FKM薄膜的介电常数和介电损耗。更重要的是,h-BNF/FKM复合薄膜还具有出色的机械韧性、优异的柔韧性、良好的附着力和阻燃性,在电子器件热管理方面具有广阔的应用前景。
Enhancing the fracture toughness of aerospace-grade carbon fibre/epoxy composites by interlaying surface-activated low-melt polyaryletherketone (LMPAEK) meshes
Dong Quan, Xuemin Wang, Jiaying Pan, Yannan Ma, Gennaro Scarselli, Guoqun Zhao
doi:10.1016/j.compositesb.2024.111824
采用表面活化低熔点聚芳醚酮(LMPAEK)网层对航空级碳纤维/环氧复合材料进行断裂韧性增强
This study proposed an innovative method for enhancing the interlaminar fracture resistance of carbon fibre/epoxy composites by incorporating structured low-melt polyaryletherketone meshes (LMPAEK) meshes. LMPAEK films were machined into structured hollow meshes and then surface-treated using high-power UV-irradiation. These treatments significantly increased the contact area and interface adhesion between the LMPAEK inserts and the composite matrix, leading to substantial improvement in the interlaminar fracture performance of the composite. Fracture test results demonstrated that the mode-I and mode-II fracture propagation energies of the LMPAEK-inserted composite at 22 °C were 1.04 times and 13.92 times higher, respectively, than those of the reference composite. Similarly, at 130 °C, their mode-I and mode-II fracture propagation energies were 1.36 times and 8.56 times higher, respectively. The remarkable fracture performance of the LMPAEK-inserted composites were attributed to the substantial plastic deformation and damage of the LMPAEK resins, which possessed exceptional mechanical properties and thermal resistance.
本研究提出了一种创新的方法来提高碳纤维/环氧复合材料的层间抗断裂能力,通过加入结构化的低熔点聚芳醚酮网(LMPAEK)网。将LMPAEK薄膜加工成结构中空网格,然后使用大功率紫外线照射进行表面处理。这些处理显著增加了LMPAEK嵌套与复合材料基体之间的接触面积和界面附着力,从而显著改善了复合材料的层间断裂性能。断裂试验结果表明,在22°C时,插入lmpaek的复合材料的i型和ii型断裂扩展能分别是参考复合材料的1.04倍和13.92倍。同样,在130℃时,它们的i型和ii型断裂扩展能分别高出1.36倍和8.56倍。插入LMPAEK的复合材料具有显著的断裂性能,这是由于LMPAEK树脂具有显著的塑性变形和损伤,具有优异的力学性能和耐热性。
Geometric tunability of interlaminar resistance
Ping Hu, Marcelo A. Dias, Michal K. Budzik
doi:10.1016/j.compositesb.2024.111839
层间阻力的几何可调性
The inherent weakness and variability in the interlaminar properties of composites and associated delamination pose significant challenges, compromising the performance of composite structures. This study investigates a strategy to tailor the apparent interlaminar resistance by altering the geometry of the interface to control crack propagation. We have developed analytical models, which propose a formulation that links the geometry, i.e. the interface width change rate and shape factor of the crack growth plane, with the reaction force–displacement curve. The results obtained, a family of power law relations followed during interlaminar crack growth, indicate that the analytical formulation is valid for all geometries tested, including those with significant width change rates; however, it may not always be easy to use or interpret. An approximated solution, constrained to slowly varying geometries, is also proposed. The limits of using this model are presented and discussed. The final validation of the models is performed using numerical and experimental approaches, considering the delamination of carbon fibre laminates. This work offers new insights into the design of composites and the fracture process in general, featuring unique shapes and improved crack resistance. It also addresses practical issues, e.g., related to composite repairs, which can enhance the performance and longevity of composite structures. Specifically, the proposed formulations can be easily adopted to obtain optimized patch geometries.
复合材料层间性能的固有弱点和可变性以及相关的分层构成了重大挑战,损害了复合材料结构的性能。本研究探讨了一种通过改变界面的几何形状来调整层间表观阻力以控制裂纹扩展的策略。我们建立了解析模型,提出了一种将裂纹扩展面的界面宽度变化率和形状因子与反力-位移曲线联系起来的公式。得到的结果表明,在层间裂纹扩展过程中遵循幂律关系,该分析公式适用于所有测试的几何形状,包括具有显著宽度变化率的几何形状;然而,它可能并不总是容易使用或解释。本文还提出了一种约束于缓慢变化几何的近似解。提出并讨论了使用该模型的局限性。考虑到碳纤维层合板的分层,采用数值和实验方法对模型进行了最终验证。这项工作为复合材料的设计和断裂过程提供了新的见解,具有独特的形状和提高的抗裂性。它还解决了实际问题,例如,与复合材料修复有关的问题,这可以提高复合材料结构的性能和寿命。具体而言,所提出的配方可以很容易地用于获得优化的斑块几何形状。
Shape memory cyclic behavior and mechanical durability of woven fabric reinforced shape memory polymer composites
Guangqing Ming, Fengfeng Li, Mingming Xu, Chengjun Zeng, Wei Zhao, Liwu Liu, Yanju Liu, Jinsong Leng
doi:10.1016/j.compscitech.2024.110866
机织增强形状记忆聚合物复合材料的形状记忆循环性能和机械耐久性
The shape memory cyclic behavior and mechanical durability of the shape memory polymer (SMP) and three woven fabrics (plain, twill, and satin weaves) reinforced shape memory polymer composite (WFR-SMPCs) are characterized to investigate the effect of woven textures on the mechanical and shape memory properties of WFR-SMPCs. Shape memory cycle test, shape memory durability test, and microscopic observation for SMP and WFR-SMPCs were carried out. Experimental results show that the SMP is temperature-sensitive, and higher temperature facilitates the shape memory performance of the material. The woven fabric reinforcements can significantly enhance the mechanical properties of the SMP matrix while still maintaining good shape recovery ratios above 98% and shape fixation ratios above 90% even though there is a slight decrease in these values. The twill WFR-SMPC displays the best mechanical performance. The satin WFR-SMPC has the highest shape recovery ratio. The twill WFR-SMPC performs the best in load-bearing capacity and recovery stress. The microscopic observations show that the rotational misalignment and bending of the fiber tows, and damage to the matrix are the main failure modes of the WFR-SMPCs at high shear strain.
研究了形状记忆聚合物(SMP)和三种机织物(平纹、斜纹和缎纹)增强形状记忆聚合物复合材料(wfr - smpc)的形状记忆循环行为和机械耐久性,探讨了机织物对wfr - smpc力学和形状记忆性能的影响。对SMP和wfr - smpc进行了形状记忆循环试验、形状记忆耐久性试验和显微观察。实验结果表明,SMP具有温度敏感性,较高的温度有利于材料的形状记忆性能。机织增强剂可以显著提高SMP基体的力学性能,同时保持良好的98%以上的形状恢复率和90%以上的形状固定率,尽管这些数值略有下降。斜纹WFR-SMPC的力学性能最好。缎面WFR-SMPC具有最高的形状恢复率。斜纹WFR-SMPC在承载能力和恢复应力方面表现最好。微观观察表明,高剪切应变下wfr - smpc的主要破坏模式是纤维的旋转错位和弯曲,以及基体的损伤。